#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/string_choices.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/proc_fs.h>
#include <linux/uaccess.h>
#include <platform/simcall.h>
#define SIMDISK_MAJOR 240
#define SIMDISK_MINORS 1
#define MAX_SIMDISK_COUNT 10
struct simdisk {
const char *filename;
spinlock_t lock;
struct gendisk *gd;
struct proc_dir_entry *procfile;
int users;
unsigned long size;
int fd;
};
static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
module_param(simdisk_count, int, S_IRUGO);
MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");
static int n_files;
static const char *filename[MAX_SIMDISK_COUNT] = {
#ifdef CONFIG_SIMDISK0_FILENAME
CONFIG_SIMDISK0_FILENAME,
#ifdef CONFIG_SIMDISK1_FILENAME
CONFIG_SIMDISK1_FILENAME,
#endif
#endif
};
static int simdisk_param_set_filename(const char *val,
const struct kernel_param *kp)
{
if (n_files < ARRAY_SIZE(filename))
filename[n_files++] = val;
else
return -EINVAL;
return 0;
}
static const struct kernel_param_ops simdisk_param_ops_filename = {
.set = simdisk_param_set_filename,
};
module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
MODULE_PARM_DESC(filename, "Backing storage filename.");
static int simdisk_major = SIMDISK_MAJOR;
static void simdisk_transfer(struct simdisk *dev, unsigned long sector,
unsigned long nsect, char *buffer, int write)
{
unsigned long offset = sector << SECTOR_SHIFT;
unsigned long nbytes = nsect << SECTOR_SHIFT;
if (offset > dev->size || dev->size - offset < nbytes) {
pr_notice("Beyond-end %s (%ld %ld)\n",
str_write_read(write), offset, nbytes);
return;
}
spin_lock(&dev->lock);
while (nbytes > 0) {
unsigned long io;
simc_lseek(dev->fd, offset, SEEK_SET);
READ_ONCE(*buffer);
if (write)
io = simc_write(dev->fd, buffer, nbytes);
else
io = simc_read(dev->fd, buffer, nbytes);
if (io == -1) {
pr_err("SIMDISK: IO error %d\n", errno);
break;
}
buffer += io;
offset += io;
nbytes -= io;
}
spin_unlock(&dev->lock);
}
static void simdisk_submit_bio(struct bio *bio)
{
struct simdisk *dev = bio->bi_bdev->bd_disk->private_data;
struct bio_vec bvec;
struct bvec_iter iter;
sector_t sector = bio->bi_iter.bi_sector;
bio_for_each_segment(bvec, bio, iter) {
char *buffer = bvec_kmap_local(&bvec);
unsigned len = bvec.bv_len >> SECTOR_SHIFT;
simdisk_transfer(dev, sector, len, buffer,
bio_data_dir(bio) == WRITE);
sector += len;
kunmap_local(buffer);
}
bio_endio(bio);
}
static int simdisk_open(struct gendisk *disk, blk_mode_t mode)
{
struct simdisk *dev = disk->private_data;
spin_lock(&dev->lock);
++dev->users;
spin_unlock(&dev->lock);
return 0;
}
static void simdisk_release(struct gendisk *disk)
{
struct simdisk *dev = disk->private_data;
spin_lock(&dev->lock);
--dev->users;
spin_unlock(&dev->lock);
}
static const struct block_device_operations simdisk_ops = {
.owner = THIS_MODULE,
.submit_bio = simdisk_submit_bio,
.open = simdisk_open,
.release = simdisk_release,
};
static struct simdisk *sddev;
static struct proc_dir_entry *simdisk_procdir;
static int simdisk_attach(struct simdisk *dev, const char *filename)
{
int err = 0;
filename = kstrdup(filename, GFP_KERNEL);
if (filename == NULL)
return -ENOMEM;
spin_lock(&dev->lock);
if (dev->fd != -1) {
err = -EBUSY;
goto out;
}
dev->fd = simc_open(filename, O_RDWR, 0);
if (dev->fd == -1) {
pr_err("SIMDISK: Can't open %s: %d\n", filename, errno);
err = -ENODEV;
goto out;
}
dev->size = simc_lseek(dev->fd, 0, SEEK_END);
set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
dev->filename = filename;
pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);
out:
if (err)
kfree(filename);
spin_unlock(&dev->lock);
return err;
}
static int simdisk_detach(struct simdisk *dev)
{
int err = 0;
spin_lock(&dev->lock);
if (dev->users != 0) {
err = -EBUSY;
} else if (dev->fd != -1) {
if (simc_close(dev->fd)) {
pr_err("SIMDISK: error closing %s: %d\n",
dev->filename, errno);
err = -EIO;
} else {
pr_info("SIMDISK: %s detached from %s\n",
dev->gd->disk_name, dev->filename);
dev->fd = -1;
kfree(dev->filename);
dev->filename = NULL;
}
}
spin_unlock(&dev->lock);
return err;
}
static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
size_t size, loff_t *ppos)
{
struct simdisk *dev = pde_data(file_inode(file));
const char *s = dev->filename;
if (s) {
ssize_t len = strlen(s);
char *temp = kmalloc(len + 2, GFP_KERNEL);
if (!temp)
return -ENOMEM;
len = scnprintf(temp, len + 2, "%s\n", s);
len = simple_read_from_buffer(buf, size, ppos,
temp, len);
kfree(temp);
return len;
}
return simple_read_from_buffer(buf, size, ppos, "\n", 1);
}
static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
char *tmp;
struct simdisk *dev = pde_data(file_inode(file));
int err;
if (count == 0 || count > PAGE_SIZE)
return -EINVAL;
tmp = memdup_user_nul(buf, count);
if (IS_ERR(tmp))
return PTR_ERR(tmp);
err = simdisk_detach(dev);
if (err != 0)
goto out_free;
if (count > 0 && tmp[count - 1] == '\n')
tmp[count - 1] = 0;
if (tmp[0])
err = simdisk_attach(dev, tmp);
if (err == 0)
err = count;
out_free:
kfree(tmp);
return err;
}
static const struct proc_ops simdisk_proc_ops = {
.proc_read = proc_read_simdisk,
.proc_write = proc_write_simdisk,
.proc_lseek = default_llseek,
};
static int __init simdisk_setup(struct simdisk *dev, int which,
struct proc_dir_entry *procdir)
{
struct queue_limits lim = {
.features = BLK_FEAT_ROTATIONAL,
};
char tmp[2] = { '0' + which, 0 };
int err;
dev->fd = -1;
dev->filename = NULL;
spin_lock_init(&dev->lock);
dev->users = 0;
dev->gd = blk_alloc_disk(&lim, NUMA_NO_NODE);
if (IS_ERR(dev->gd)) {
err = PTR_ERR(dev->gd);
goto out;
}
dev->gd->major = simdisk_major;
dev->gd->first_minor = which;
dev->gd->minors = SIMDISK_MINORS;
dev->gd->fops = &simdisk_ops;
dev->gd->private_data = dev;
snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
set_capacity(dev->gd, 0);
err = add_disk(dev->gd);
if (err)
goto out_cleanup_disk;
dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev);
return 0;
out_cleanup_disk:
put_disk(dev->gd);
out:
return err;
}
static int __init simdisk_init(void)
{
int i;
if (register_blkdev(simdisk_major, "simdisk") < 0) {
pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
return -EIO;
}
pr_info("SIMDISK: major: %d\n", simdisk_major);
if (n_files > simdisk_count)
simdisk_count = n_files;
if (simdisk_count > MAX_SIMDISK_COUNT)
simdisk_count = MAX_SIMDISK_COUNT;
sddev = kmalloc_objs(*sddev, simdisk_count);
if (sddev == NULL)
goto out_unregister;
simdisk_procdir = proc_mkdir("simdisk", 0);
if (simdisk_procdir == NULL)
goto out_free_unregister;
for (i = 0; i < simdisk_count; ++i) {
if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
if (filename[i] != NULL && filename[i][0] != 0 &&
(n_files == 0 || i < n_files))
simdisk_attach(sddev + i, filename[i]);
}
}
return 0;
out_free_unregister:
kfree(sddev);
out_unregister:
unregister_blkdev(simdisk_major, "simdisk");
return -ENOMEM;
}
module_init(simdisk_init);
static void simdisk_teardown(struct simdisk *dev, int which,
struct proc_dir_entry *procdir)
{
char tmp[2] = { '0' + which, 0 };
simdisk_detach(dev);
if (dev->gd) {
del_gendisk(dev->gd);
put_disk(dev->gd);
}
remove_proc_entry(tmp, procdir);
}
static void __exit simdisk_exit(void)
{
int i;
for (i = 0; i < simdisk_count; ++i)
simdisk_teardown(sddev + i, i, simdisk_procdir);
remove_proc_entry("simdisk", 0);
kfree(sddev);
unregister_blkdev(simdisk_major, "simdisk");
}
module_exit(simdisk_exit);
MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
MODULE_LICENSE("GPL");
